Add MIME mapping in web.config for IIS Express

<system.webServer>
     <staticContent>
      <remove fileExtension=".woff"/>
      <mimeMap fileExtension=".woff" mimeType="application/font-woff" />
      <mimeMap fileExtension=".woff2" mimeType="font/woff2" />
    </staticContent>
  </system.webServer>

Putting it in the "web.config" works fine. The problem was that I got the MIME type wrong. Instead of font/x-woff or font/x-font-woff it must be application/font-woff:

<system.webServer>
  ...
  <staticContent>
    <remove fileExtension=".woff" />
    <mimeMap fileExtension=".woff" mimeType="application/font-woff" />
  </staticContent>
</system.webServer>

See also this answer regarding the MIME type: https://stackoverflow.com/a/5142316/135441

Update 4/10/2013

Spec is now a recommendation and the MIME type is officially: application/font-woff

If anybody encounters this with errors like Error: cannot add duplicate collection entry of type ‘mimeMap’ with unique key attribute and/or other scripts stop working when doing this fix, it might help to remove it first like this:

<staticContent>
  <remove fileExtension=".woff" />
  <mimeMap fileExtension=".woff" mimeType="application/font-woff" />
</staticContent>

At least that solved my problem

I know this is an old question, but...

I was just noticing my instance of IISExpress wasn't serving woff files, so I wen't searching (Found this) and then found:

http://www.tomasmcguinness.com/2011/07/06/adding-support-for-svg-to-iis-express/

I suppose my install has support for SVG since I haven't had issue with that. But the instructions are trivially modifiable for woff:

• Open a console application with administrator privilages.
• Navigation to the IIS Express directory. This lives under Program Files or Program Files (x86)

• Run the command:

  appcmd set config /section:staticContent /+[fileExtension='woff',mimeType='application/x-woff']

Solved my problem, and I didn't have to mess with some crummy config (like I had to to add support for the PUT and DELETE verbs). Yay!